In various electrical and electronic systems, connector pins and guide socket connectors have been used to assemble circuit modules into a support frame or similar structure. As illustrated in FIG. 1 of the present specification, a module assembled using such prior art connectors typically requires varying degrees of force to achieve full insertion of its pins into the connector springs associated with the guide sockets. Initially, the module encounters no or very slight resistance as its pins pass into the empty sockets, as shown in Region A. However, as the connector pins initially spread the connector springs, a marked increase in insertion force is experienced, as shown in Region B. Once the connector springs have been deflected for most of the pins, the insertion force drops off somewhat, as shown in Region C. The pins reach the end of their travel in Region D. For example, in the connector shown in U.S. Pat. No. 3,915,537, the module encounters no resistance when the pins move into their guide sockets, small resistance when the pins are moved sideways into contact with the connector springs (Region A), increasing resistance as the connector springs are spread (Region B), and reduced resistance as the connection is completed (Region C). The disclosure of this patent is hereby incorporated by reference in the present specification.
Typically, it is desired to stop insertion when all of the pins are in Region C. However, due to unavoidable variations from pin to pin and from guide socket connector to guide socket connector, the force versus displacement curve for each circuit module and connector assembly will be somewhat different. Ideally, the pins should be moved a fixed distance from the start of Region B into the middle of Region C.
Various approaches have been followed to achieve the desired degree of pin insertion. In U.S. Pat. No. 3,784,954, the circuit module or printed circuit board is provided with bolt or stud elements accurately positioned relative to the connector pins. Engagement arms pivoted to the support frame include cam surfaces which bear on the studs upon rotation of the arms, thus inserting the pins into or removing them from the connectors. Other applications are known in which accurately positioned tabs on the module are contacted by actuator pins on an associated pivoted bail. Provision of such tabs or studs increases the cost of the module and may undesirably limit the space available on the module for circuit elements or connector pins. Accurately positioned notches in the module have also been proposed, but suffer from similar and other disadvantages.
Thus, a need has continued to exist for a mechanism for connecting and disconnecting circuit modules without requiring that the dimensions of the module be carefully controlled so that the connector pins of the module will properly engage with and disengage from the associated guide socket connectors.